Add 'Make anonymous function static' feature

[DoctorKrolic]

Closes: #45832

[DoctorKrolic]

@CyrusNajmabadi PTAL

[CyrusNajmabadi]

LGTM. Let me know if you want to fixup the tests or not. I'm ok with them going in in the current state.

[CyrusNajmabadi]

Thanks!

[DoctorKrolic]

Need failed pipelines restart here

[CyrusNajmabadi]

CI failure is legit:

Missing entry in 'D:\a\_work\1\s\src\Features\RulesMissingDocumentation.md'. Please add the below entry to this file to fix the build:
  IDE0320 | <[https://learn.microsoft.com/dotnet/fundamentals/code-analysis/style-rules/ide0320>](https://learn.microsoft.com/dotnet/fundamentals/code-analysis/style-rules/ide0320%3E) | Make anonymous function static |
D:\a\_work\1\s\src\Features\Core\Portable\Microsoft.CodeAnalysis.Features.csproj(170,5): error MSB3073: The command ""D:\a\_work\1\s\.dotnet\dotnet.exe" --roll-forward major "D:\a\_work\1\s\artifacts\bin\GenerateRulesMissingDocumentation\Release\net8.0\GenerateRulesMissingDocumentation.dll" "-validateOnly:True" "D:\a\_work\1\s\src\Features" "D:\a\_work\1\s\artifacts\bin\\" "Release"" exited with code 1.

Build FAILED.

Sorry the UI is unclear here.

[CyrusNajmabadi]

you just need to add a line to that file. our docs team will then doc this in the future.

[DoctorKrolic]

CI failed again... This time doesn't seem to be a legit failure

[CyrusNajmabadi]

Thanks. Have notified the test owner of hte flakeyness issue.

[CyrusNajmabadi]

Thanks!

[cremor]

Did this feature make it into 17.11 (as suggested by the assigned milestone)? Because I'm currently running 17.11.4 and SDK 8.0.400 and I can't get the analyzer to show up with the "before" examples in #45832

[DoctorKrolic]

This analyzer is hidden by default so that existing code doesn't get too noisy. If you want this diagnostic to be shown in the diagnostic list, upgrade its severity to 'suggestion' or higher

[cremor]

I did test it with this .editorconfig setting:

csharp_prefer_static_anonymous_function = true:suggestion

Code:

public void M(Func<int, int> func) { }

public void T()
{
    M(x => x + 1); // before
    M(delegate (int x) { return x + 1; }); // before
}